• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.15-20
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• 2009

The results of crack evaluation by conventional UT(Ultrasonic Test)is highly depend on the inspector's experience or knowledge of ultrasound. Phased array UT system and its application methods for small crack length evaluation will be a good alternative method which overcome present UT weakness. This study was aimed at checking the accuracy of crack length evaluation method by electronic scanning and discuss about characteristics of electronic scanning for crack length evaluation. Especially ultrasonic phased array with electronic scan technique was used in carrying out both sizing and detect ability of crack as its length changes. The response of ultrasonic phased array was analyzed to obtain the special method of determining crack length without moving the transducer and detect-ability of crack minimal length and depth from the material. A method of crack length determining by electronic scanning for the small crack is very real method which has it's accuracy and verify the effectiveness of method compared to a conventional crack length determination.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.1
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• pp.15-20
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• 2008

Contaminated sediments are the actual cause for deterioration of coastal-ecosystem. So the developed countries have been in the process of making an effort to develop new techniques for monitoring and solving this problem since 1960. In this research, suction type pump dredging system of pilot size for collecting the filth from the seabed has been designed and manufactured that can prevent or minimize the secondary pollution by filth diffusion. For the practical use, the application possibility of the developed system has been checked through a system performance test. And, the evaluation of system performance according to the underwater body type has been carried out for system optimization by using CFD. The performance tests for checking the efficiency of sediment collecting system are done under two conditions i.e. when the system is non-operational and when the system is self-propelled. The results of this research showed the possibility of the development of dredging system to remove just the upper parts of filth from seabed.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.205-210
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• 2015

The auto industry has significantly evolved to the extent that much attention is paid to M2M (Machine-to-Machine) communication. In M2M communication which was first used in meteorology, environment, logistics, national defense, agriculture and stockbreeding, devices automatically communicate and operate in accordance with varying situations. M2M system is applied to vehicles, specifically to device-to-device communication inside cars, vehicle-to-vehicle communication, communication between vehicles and traffic facilities and that between vehicles and surroundings. However, communication systems are characterized by potential intruders' attacks in transmission sections, which may cause serious safety problems if vehicles' operating system, control system and engine control parts are attacked. Thus, device-to-device secure communication has been actively researched. With a view to secure communication between vehicular devices, the present study drew on hash functions and complex mathematical formulae to design a protocol, which was then tested with Casper/FDR, a tool for formal verification of protocols. In brief, the proposed protocol proved to operate safely against a range of attacks and be effective in practical application.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.65-76
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• 2014

In this paper, we propose a high-level programming language for packet processing called eFlowC and it supporting programming development environment. Based on the C language which is already familiar and easy to use to program developers, eFlowC maintains the similar syntax and semantics of C. Some features that are unnecessary for the packet processing has been removed from C, eFlowC is highly focused on performing packet data, database, string byte information checking and event processing. Design high-level programming languages and apply an existing language or compiler technology, language function and compilation process that is required for packet processing will be described. In order to use the DPIC device such as X11, we designed a virtual machine eFVM that takes into account the scalability and portability. We have evaluated the utility of the proposed language by experimenting a variety of real application programs with our programming environment such as compiler, simulator and debugger for eFVM. As there is little research that devoted to define the formats, meanings and functions of the packet processing language, this research is significant and expected to be a basis for the packet processing language.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.136-146
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• 2016

The purpose of this study was to investigate whether there was a gender difference in motivating university students to decrease their sodium intake and to identify effective motivating factors. Within the protection motivation theory (PMT) framework, a survey questionnaire was developed to measure participants' perceptions on the severity of and the vulnerability to risk of serious diseases due to the high sodium intake, as well as the effectiveness (response efficacy) and the ability to perform preventive measures (self-efficacy). Behavioral intentions on five specific practices (checking nutrition label, consuming more fruits and vegetables, consuming less soups, avoiding spicy and pungent food, purchasing less instant or restaurant foods) related to decreasing sodium intake were also included. A total of 294 usable response data were collected from university students (92 male, 202 female) in Busan and Gyeongnam in June 2015 and analyzed using IBM SPSS 22. Severity was the highest (4.04) PMT factor followed by response efficacy (3.72), self-efficacy (3.42), and vulnerability (3.26). Compared to male students, female students thought that the threat was more severe (t=6.035, p<0.001) and reducing sodium intake would be effective to prevent serious illnesses (t=4.724, p<0.001), but their vulnerability and self-efficacy perceptions were not different from male students. Among the five items measuring behavioral intention, female students were more likely to increase fruits and vegetables consumption (t=3.811, p<0.001), while male students were more likely to avoid spicy and pungent foods (t=2.336, p=0.020). Based on findings of this study, the recommended strategy to effectively motivate university students to lower their sodium consumption level is the development of campaign focused on increased vulnerability perception, response efficacy, and ease of practicing preventive measures instead of emphasizing the severity of the consequences.

• Korean journal of food and cookery science
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• v.23 no.3 s.99
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• pp.378-387
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• 2007

In this study, we investigated the application of HACCP for a prepared side dish of sweet potato stems, within a free meal service system for the elderly in the Sungnam area. Total bacterial counts (TBC) and levels of coliforms and Esherichia coli (E.coli) were analyzed through an eight step cooking process. The TBCs of the raw samples ranged between 3.30 and 1.37${\times}10^4$ CFU/g per 100 cm$^2$ The trimmed, blanched, and drained sweet potato stems showed a mean TBC value of 1.37${\times}10^4$ CFU/g, and the level of coliforms was 1.48${\times}10^3$ CFU/g. Among the eight samples, however, after stir-frying and serving, the TBC decreased to a standard satisfactory level, and a coliforms and E. coli were not found. A five step process was used and samples were taken to check the microbial quality of the cook and cooking equipment. Here we tested for TBC, coliforms, Staphylococcus aureus (S. aureus), and Salmonella. Specifically, the TBC and number of coliforms were examined on the cook's hand's, cutting board, and knife, as they represented hazards for cross-contamination. The three inspection steps of preparation of the trimmed, rinsed, blanched, and drained sweet potato stems, cook's' hands, cutting board and knife were all considered CCPs, and a manual of cooking process management was established to improve the risk factors in this study. In conclusion, this study reinforces that microbiological analysis is as a valuable tool for checking what points and stages of the cooking process must be controlled.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2006.06a
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• pp.288-293
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• 2006

최근 반도체 개발 및 제조부문에서는 급속도로 성장한 Mobile 시장과 Digital Consumer Trend 에 주도적으로 대응하고자 빠른 속도의 기술적 변화를 추진하여 왔으며, 이에 따라 현장에서 발생하는 기술적 문제의 유형 또한 점점 복잡 다양해지고 있다. 기존 Commodity 제품의 경우, 세대 전환이 느리게 진행되어, 이에 수반되는 기술적 문제의 난이도와 그 발생 종류가 현재 대비 상대적으로 단순하였다. 그러나 최근 다품종 주문형 제품비중 확대로, 발생되는 문제점들이 Field Application 과 tight 한 연관성을 지니고 있어, 문제의 발생 경로, 원인 파악과 해결 대책 수립에 상당한 초기대응 시간을 필요하며, 관련 부서와의 실시간 협업 및 Cross-Checking을 통하지 않고서는 문제에 대한 최적 Solution 을 결정하기 힘든 현실이 되었다. 이러한 기술 이슈 해결 과정에 기 발생했던 유사 이슈 처리 과정 및 결과 자료가 문제 해결에 크게 기여할 수 있으나, 종래의 지식관리 시스템 체계로는 이러한 실무 형 지식을 획득하기 어려운 부분이 한계점으로 지적되고 있다. 본 논문에서는 이러한 문제점 개선이 가능한 실무형 지식 관리 (AKM: Actual Knowledge Management) 기반의 기술적 이슈 추적 관리 시스템(TITS: Technical Issue Tracking System) 구축 사례를 제시하고자 한다. TITS 는 1) 기술 이슈의 발의 및 전파 기능과 2) 이슈 해결을 위한 Action Item 부여 및 의견 교환 기능 3) 해결된 이슈의 처리 결과 등록 기능 4) 유사 이슈 사례 검색 기능 등의 크게 4 개 모듈오 구성 되어있다. 이 시스템을 통해 반도체 엔지니어들은 기술적 이슈의 발생 시점부터, 원안분석, 대책 협의 ; Action Item 수립 등 문제 해결 과정과 결과 등록 시점까지 Real time Tracking이 가능해 졌으며, 본 시스템을 통해 처리된 모든 기술적 이슈 정보는 Issue Case Database 에 분류 저장되어, 향후 유사 이슈 발생 시, 이를 활용함으로써, 빠른 초기 대응 및 문제 해결에 직접적인 도움을 받을 수 있게 되었다.

• Steel and Composite Structures
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• v.22 no.1
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• pp.63-77
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• 2016

Top-down construction is a construction technique in which pit excavation and structure construction are conducted simultaneously. Reducing construction time and minimizing noise and vibration which affect neighboring structures, the technique is widely employed in constructing downtown structures. While H-steel columns have been commonly used as core columns, concrete filled steel tube (CFT) columns are at the center of attention because the latter have less axial directionality and greater cross-sectional efficiency than the former. When compared with circular CFT columns, square CFT columns are more easily connected to the floor structure and the area of percussion rotary drilling (PRD) is smaller. For this reason, square CFT columns are used as core columns of concrete encased and filled square (CET) columns in underground floors. However, studies on the structural behavior and concrete stress transfer of CET columns have not been conducted. Since concrete is cast according to construction sequence, checking the stress of concrete inside the core columns and the stress of covering concrete is essential. This paper presents the results of structural tests and analyses conducted to evaluate the usability and safety of CET columns in top-down construction where CFT columns are used as core columns. Parameters in the tests are loading condition, concrete strength and covering depth. The compressive load capacity and failure behavior of specimens are evaluated. In addition, 2 cases of field application of CET columns in underground floors are analyzed.

• Journal of the Korean School Mathematics Society
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• v.8 no.2
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• pp.117-143
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• 2005

This study is aimed at checking on the extent of practical use of CAI in mathematical classes in secondary schools, thus seeking a way of activating the practical use of CAI, with computer networks being widely used for education. This research was conducted among some 120 mathematics teachers and 350 students in middle and high schools in the City of Kunsan, with questionnaires designed to survey the extent and effectiveness of the use of CAI, the teachers and students' awareness of CAI. In consequence, this research shows the following: The use of CAI was of considerable help in conducting mathematics classes, along with CAI used in a more effective way, but education materials concerning CAI were poorly managed and not a few teachers was negative toward the use of CAI in mathematics classes. In short, the practical use of CAI was unsatisfactory, probably due to the lack of application ability on the part of teachers caused by the perfunctory teachers' training. In conclusion, the practical use of CAI in classes can be activated as follows: CAI apparatuses and other teaching aids should be systematically managed by experts; high-quality CAI programs need to be developed to help teachers conduct effective classes; teachers should be positively encouraged to make practical use of CAI through teachers' training and a plan of obligating teachers to use CAI for one or two fixed class hours in a week may be strongly recommended.

• Journal of Nutrition and Health
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• v.35 no.8
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• pp.886-895
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• 2002

Introduction and application of virtual education has been rapidly increased in these days. A variation of information communication technology has an effect on education in interconnect with network as internet in the world that exceed the limit of time and regional. Computer and network communication technology through the medium of internet make an entrance cyber education as a new education paradigm. It must be affective on learner who have various educational characteristics and requirements. It begins to appear quality, quantity improvements of knowledge and the development of information technology that web based cyber education. This study was conducted to develop the web based education program and to evaluate the effectiveness of learning satisfaction and accomplishment and to compare the cyber lecture system with the traditional lecture system During the second semester of 2001, this study was investigated 317 registered students in a "Food and Culture" class at Kyungwon University. The data were obtained from pre and post-study with self-administered questionnaire. The evaluation and satisfaction score of students who were registered in cyberclass was negative tendency to compare pre with post-test scores, because of insuffciency of computer-aided lecture system. The major problem was inconvenient in checking system for connecting times in cyberclass which was one of evaluation point in final score. Another problem was frequently disconnection during cyber studying and not to concentrate each time in the cyber lecture because of eye fatigue, boring due to less interesting contents than other newly developed web-site. The students was prefer to mix type of the cyber and traditional lecture type class. The result of final score an each class, the score of cyber class (71.36 $\pm$ 22.44) was significantly lower than other groups (mixed type : 76.66 $\pm$ 19.99, traditional type :79.17 $\pm$ 15.72) (p < 0.05). Cyber class was attempted to present a useful and interesting teaching and learning tool which can be applied successfully in a longer term. The result suggest that various teaching and learning strategies should be developed considering the fact that the student learn alone most in time.t in time.